In a large mixing bowl, whisk together 2 cups of all-purpose flour, 1 tablespoon of granulated sugar, and 1/2 teaspoon of salt until combined. Cut in 1 cup of cold unsalted butter until the mixture resembles coarse crumbs. Gradually add 3-4 tablespoons of cold water, mixing until a dough forms. Shape it into a disk, wrap in plastic, and refrigerate for at least 1 hour.

In a medium bowl, beat 8 ounces of softened cream cheese, 1/4 cup of powdered sugar, and 1 teaspoon of vanilla extract with an electric mixer until smooth. Optionally, fold in 1/4 cup of fruit preserves or fresh berries. Set the filling aside, and preheat your oven to 400°F (200°C).

Once the dough is chilled, roll it out into a rectangle about 1/4 inch thick and cut into 4x4 inch squares. Keep the squares chilled briefly while you assemble.

Place a generous spoonful of the filling in the center of each square. Fold the corners into the center, pinch to seal, and arrange on a parchment-lined baking sheet.

Whisk together 1 egg and a splash of milk for the egg wash. Brush over each Danish and bake for 15-20 minutes until golden brown. Allow to cool slightly before serving.